In response to a user query, an existing web search engine can return direct answers, in addition to sets of documents, for example, by displaying the string “29,028 feet” in response to the query “Mount Everest height”. Interaction with a question-answering system generates user expectations about the ability of the system to answer classes of queries. For example, if a search engine returns an answer for “Mount Bachelor height”, the system creates an expectation in the user by which the system is then also expected to know (have data about) the heights of all mountains of similar saliency (or relevancy). Failing to return a direct answer for one or more questions about other mountain heights then negatively impacts the user expectation of reliability in the system, thereby generating user dissatisfaction and eventually creating abandonment by the user.